Multi camera for stereo
You could parent a second camera to the first one. If you duplicate the first one, select the second one and in the dropdown menu of the Dopesheet (Action Editor mode) click on the X button to unlink the action from the selection. Now the second camera will follow the first one. The only problem is that the gravity center is the first camera, but maybe it doesn't bother you.

Maybe the best solution is this one: Create an empty. Keep the empty selected and in the dropdown menu of the Dopesheet (Action Editor mode) select the animation that you've already created for your camera, the animation is assigned to the empty. Now select your camera and on the right of this same dropdown menu click on the X button to unlink the action from the selection. Now only the empty will move. Parent your camera to the empty. Create a second camera and same thing, parent it to the empty. Both the 2 cameras will follow the empty.

Does it answer?